Thermal artefact after diathermy loop excision and laser excision cone biopsy

Dalrymple C, Russell P. Thermal artefact after diathermy loop excision and laser excision cone biopsy. Int J Gynecol Cancer 1999; 9 : 238–242.
Whether or not thermal artefact precludes accurate histopathologic assessment of excision biopsies of the uterine cervix is currently controversial. Some authors state that margins cannot be assessed at all while others feel that the pathologist can 'see through' the artefact in the majority of cases. Over a 7-month period, 164 patients had loop excision and 84 patients had laser cone biopsy. The zone of coagulation at the specimen periphery was measured and the adequacy of excision assessed. The average width for this zone of coagulation in diathermy loop was 0.32 mm and for laser cone biopsies was 0.31 mm. In 12% of the loop specimens the line of excision was compromised by dysplasia or its assessment was rendered uncertain by thermal artefact. This was far more common in fragmented specimens (20%) compared to those removed as a single specimen (6%). In this study, 40% of patients had fragmented loop specimens. Thus, in attempting to replace cone biopsy with loop excision, we are asking pathologists to reassemble a pathologic jigsaw, then look through the thermal artefact for a decision on margins. We believe that this fragmentation should preclude the use of loop excision for lesions which would previously have been managed by cone biopsy.     

Autologous Versus Allogeneic Transfusion in Aortic Surgery: A Multicenter Randomized Clinical Trial

OBJECTIVE: To evaluate the efficacy of acute normovolemic hemodilution (ANH) and intraoperative cell salvage (ICS) in blood-conservation strategies for infrarenal aortic surgery. SUMMARY BACKGROUND DATA: Recent concerns over the risks of transfusion-related infection have resulted in sharp rises in the cost of blood preparations. Autologous transfusion may be a safe alternative to allogeneic transfusion, which has been associated with immune modulation and postoperative infection. METHODS: This multicenter prospective randomized trial compared standard transfusion practice with autologous transfusion combining ANH with ICS in 145 patients undergoing elective aortic surgery. The primary outcome measures were the proportion of patients requiring allogeneic blood and the volume of allogeneic transfusion. The secondary outcome measures were the frequency of complications, including postoperative infection, and postoperative hospital stay. RESULTS: The combination of ANH and ICS reduced the volume of allogeneic blood transfused from a median of two units to zero units. The proportion of patients transfused was 56% in allogeneic and 43% in autologous. There were no significant differences in complications or length of hospital stay. CONCLUSIONS: Both ANH and ICS were safe and reduced the allogeneic blood requirement in patients undergoing elective infrarenal aortic surgery.     

Subpulmonary pneumothorax.

Seven cases of subpulmonary pneumothorax are presented: four due to penetrating injury, two to blunt trauma and one to osteosarcoma metastasis. The typical and diagnostic appearance is a basal band of radiolucency bounded above by the thin hair-line of visceral pleura paralleling the dome of the hemi-diaphragm. When partially clotted blood is also present, the appearance becomes less typical and has to be differentiated from traumatic diaphragmatic herniation of bowel and from traumatic pneumatocoele by barium studies and by decubitus radiographs respectively. It is the bridge-like disposition of the pleural cavity between the dome of the hemi-diaphragm and the hollowed concavity of the lung base which allows pneumothorax to collect in it. It is rarely seen because blebs and bullae which are the commonest causes of pneumothorax are most often located in the upper zones.     

In vivo and in vitro binding of C4 molecules on red cells: a correlation of numbers of molecules and agglutination

The fourth component of human complement (C4) is one that is essential to the antibody-mediated classical activation pathway. C4d, present on all normal and most patient red cells (RBCs), may be detected by the human antisera anti-Rodgers (Rg) and -Chido (Ch). A study has been made of the Rg/Ch antigens on normal and patient RBCs in an attempt to understand the mechanism by which C4 is bound to normal RBCs in the absence of RBC antibodies (Abs). Because RBCs from C1q-deficient patients express Rg/Ch, it seems that C1q is not essential for C4 binding. Treatment of normal RBCs with proteolytic enzymes, including trypsin, eliminated positive reactions with anti-Rg/Ch even though the C4d fragment is considered to be resistant to cleavage by trypsin. By correlating agglutination reactions with numbers of bound C4d and C3d molecules, it is evident that both C4d and C3d were affected by trypsin treatment and that anti-Rg/Ch were not capable of agglutinating RBCs with less than 50 molecules of bound C4d. It is concluded that trypsin-sensitive and -insensitive RBC membrane structures may both act as acceptors for C4. RBCs with null phenotypes of the major blood group systems all expressed Rg/Ch antigens, so none of the structures that carry these antigens act preferentially as acceptors for C4.     

Studies on the mechanism of bacterial resistance to complement-mediated killing. II. C8 and C9 release C5b67 from the surface of salmonella minnesota S218 because the terminal complex does not insert into the bacterial outer membrane

The mechanism for consumption of terminal complement components and release of bound components from the surface of serum-resistant salmonella minnesota S218 was studied. Consumption of C8 and C9 by S218 occurred through interaction with C5b67 on the bacterial surface because C8 and C9 were consumed when added to S218 organisms previously incubated in C8-deficient serum and washed to remove all C5b67 on the bacterial surface because C8 and C9 were consumed when added to S218 organisms previously incubated in C8- deficient serum and washed to remove al but cell bound C5b67. Rapid release of (125)I C5 and (125)I C7 from the membrane of S218 was dependent on binding of C8 because (125)I C5 and (125)I C7 deposition in C8D serum was stable and was twofold higher in C8D than in PNHA, and addition of purified C8 or C8 and C9 to S218 previously incubated in C8D serum caused rapid release of (125)I C5 and (125)I C7 from the organism. Analysis by sucrose density gradient ultracentrifugation of the fluid phase from the reaction of S218 and 10 percent PNHS revealed a peak consistent with SC5b-9, in which the C9:C7 ratio was 3.3:1, but the NaDOC extracted bound C5b-9 complex sedimented as a broad peak with C9:C7 of less than 1.2:1. Progressive elution of C5b67 and C5b-9 from S218 but not serum-sensitive S. minnesota Re595 was observed with incubation in buffers of increasing ionic strength. Greater than 90 percent of the bound counts of (125)I C5 or (125)I C9 were released from S218 by incubation in 0.1 percent trypsin, but only 57 percent of (125)I C9 were released by treatment of Re595 with trypsin. These results are consistent with the concept that C5b-9 forms on the surface of the serum-sensitive S. minnesota S218 in normal human serum, but the formed complex is released and is not bactericidal for S218 because it fails to insert into hydrophobic outer membrane domains.     

Complement activation by artificial blood substitute Fluosol: in vitro and in vivo studies

A perfluorocarbon blood substitute, Fluosol, is undergoing clinical trials as an adjunct to chemotherapy. The adverse effects associated with its administration have been postulated to result from complement activation. When gel electrophoresis and Western blotting of Fluosol are used after its incubation with serum, activated C3 and factors Bb and H are bound to the Fluosol particles in a time-dependent fashion, which suggests that complement activation with Fluosol, as does that with zymosan, occurs on the surface of the particles. Paradoxically, it is found, both by the measurement of Fluosol-bound C3d and by fluid-phase C5a, that lower concentrations of Fluosol cause greater amounts of complement activation, which suggests a complex interaction of activators and inhibitors that changes as the available surface area is decreased. Studies performed with bystander red cell-bound C3d demonstrated in vivo complement activation occurring in six patients receiving Fluosol as an adjunct to chemotherapy for colon cancer. In two patients, there was a marked increase in red cell-bound C3d after Fluosol infusion; these two patients also developed adverse reactions during Fluosol infusion. These studies suggest that the Fluosol surface plays a major role in the initiation and regulation of complement activation that is seen during Fluosol infusion.